1. Field of the Invention
The present invention relates to dishwashers, and more particularly to entry points of conveyor-type dishwashers, whether conveyor-belt machines or basket transport machines, with a trough-rinsing system integrated into the entry point.
2. Prior Art
DE 44 28 738 A1 discloses a conveyor-type dishwashing machine comprising a preliminary cleaning stage, a plurality of main rinsing stages and an after-rinsing stage. A heat exchanger which serves to recover heat is provided. In order to improve the access, the possibility of cleaning and the efficiency of the heat exchanger, the latter is arranged within the preliminary cleaning stage of the conveyor-type dishwashing machine under the conveyor of the items to be cleaned in such a manner that heated washing water can drop directly onto the heat exchanger surface. The heat exchanger surface is expediently designed as a smooth flat cooling plate and simply arranged below the entry trough. The pipes of a further heat exchanger surface, through which cool fresh water is supplied, can run in or below the cooling plate. Specially designed collecting troughs can be provided for the pipe supplying the washing water to a cleaning stage.
DE 198 36 739 A1 discloses a dishwashing machine which has a collecting device for washing water and an outlet device and also a centrifugal separator for the washing water. In order to increase the cleaning action and to reduce the detergent requirement, the clean water which is guided upward out of the centrifugal separator is supplied directly to a waste water spraying device of a treatment zone. In the at least one treatment zone, at least one collecting container for washing water is arranged below the rinsing device. Said collecting container is connected to a discharge pipe and has a level limitation for the washing water. From the collecting container, a supply device runs to the spraying device, within which a recirculating pump is arranged.
In the centrifugal separator, which is supplied with washing water under pressure from the collecting container via a supply pipe and a recirculating pump, the washing water is separated into largely clean water which is conducted upward into the treatment zone above the collecting container, and into dirt water which is conducted into the waste pipe. The clean water from the centrifugal separator is supplied as spray water directly to the water-spraying device for the items to be cleaned.
The publication “Bandtransportautomat B-Tronic, Das Chemiesparsystem CSS, CSS Top . . . bis zu 80% Einsparpotential” [B-Tronic Automatie Conveyor-Belt machine, Chemical saving system CSS, CSS Top . . . up to 80% potential savings] reveals an extended entry tunnel for an automatic conveyor-belt machine. An integrated, additional preliminary rinsing-off system with a dedicated tank is arranged within the extended entry tunnel. Furthermore, permanent filtering of suds is implemented via two cyclones, and intermediate rinsing is possible. Within the intermediate rinsing context, fresh water is removed from the pump-operated final-rinsing zone and is conducted into the entry tunnel of extended design such that food residues can be highly effectively rinsed off even before the regular washing and rinsing zones. This firstly results in minimal emulsifying of fats and oils and, secondly, a heat exchanger for virtually cost-free preliminary heating of fresh water can be provided by this solution.
In the case of the conveyor-type dishwashers known from the prior art, whether conveyor-belt machines or basket transport machines, a trough base is generally provided on the unclean side within the machine entry point. A transporting belt which is preferably of endless design and on which different items to be cleaned are loaded automatically or manually either in catch pegs or in transporting baskets circulates above the trough base. During loading of the transporting means, food residues, serviettes, paper or other waste drop off or drip off from the items to be cleaned and are either collected by previously inserted covering sieves which entirely or partially cover the trough base, or drop directly onto the trough base, which results in an increased outlay on cleaning the trough base in the entry region at the end of operation.
The use customary nowadays of covering sieves, whether large-mesh or fine-mesh sieves, has a number of disadvantages. The covering sieves only collect the dirt which is larger than the opening diameter of the openings of the covering sieve. Dirt fragments which pass through the covering sieves remain on the trough base. The covering sieves are to be regularly emptied and cleaned, since otherwise there is a risk of the sieve plate becoming clogged or the covering sieves becoming overfilled. The removal of the covering sieves which are partially or completely filled with dirt and are therefore heavy is not user-friendly for ergonomic reasons. In order to clean the heavy covering sieves, the entire rinsing process has to be interrupted, depending on the location at which the covering sieves are used, and therefore the use of covering sieves and the cleaning, which is inevitably associated therewith, after the end of operation cause an additional expenditure of time and therefore additional costs.
In order to provide a remedy, structures have been devised, in which the food residues, some of which drop onto the trough base, are washed away by a trough-rinsing means into a dirt-collecting sieve. Said trough-rinsing means comprises at least one nozzle which is mounted in the trough base and which, during the rinsing mode, produces a thin water film which flows in the direction of a dirt-collecting sieve which may be present. However, this thin and therefore low-energy water film can only convey the smallest dirt fragments which pass through the sieves to the dirt-collecting sieve; larger dirt particles inevitably remain stuck to the trough base. This necessitates the use of large covering sieves and has the disadvantage that large food residues cannot be conveyed in the direction of the dirt-collecting sieve by the only thin and low-energy water film which flows along the slightly inclined trough face.